Stator and resolving method and device thereof

ABSTRACT

The method for resolving the stator having a coil disposed in the slots provided around an inner circumferential face of a cylindrical iron core and having an opening portion includes a step of enlarging the opening portion of the slot, and a step of extracting the coil from the slot.

This is a divisional of application Ser. No. 10/635,611 filed Aug. 7,2003. The entire disclosure of the prior application Ser. No. 10/635,611is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a stator, and a method and device forresolving the stator, in which the coil is easily resolved.

2. Description of the Related Art

A conventional method for resolving the stator included deleting an ironcore projection forming a bottleneck opening of slot in an iron coremiddle hole, pressing a coil end portion exposed out of the iron core atone end of the iron core toward the center of iron core around theentire circumference to extrude the coil side out of the slot into theiron core middle hole, reducing an apparent outer diameter of coil atthe end portion of the coil under the iron core middle hole, andpressing the coil end portion in an axial center direction to extractthe coil out of the iron core middle hole to separate the iron core ofthe stator and the coil (e.g., refer to document 1). Anotherconventional method for resolving the stator for an AC dynamo forvehicle was disclosed, including a step of cutting a part of onetransition portion of a stator iron core in an axial direction, and astep of pulling out an electrical conductor in the axial direction.Moreover, the stator for AC dynamo was disclosed in which the statorwindings are not impregnated with resin, whereby the stator iron coreand the stator windings are easily separated to be reusable (e.g., referto document 2).

[Document 1]

JP-A-5-138453 (pages 2 and 3, FIG. 1)

[Document 2]

JP-A-11-75334 (pages 2 to 5, FIGS. 2 to 5)

The method for resolving the stator as disclosed in JP-A-5-138453 hadthe problem that it took a longer time to resolve the stator, becausethe iron core projection forming the bottleneck opening of slot wasdeleted, and when the coil was treated with vanish, the resolvingefficiency was lower, because the coil was not simply taken out of theiron core. Also, the method for resolving the stator as disclosed inJP-A-11-75334 had the problem that the coil had a lower yield ofwithdrawal, because the coil needed to be cut out, and when the coil wastreated with vanish, the resolving efficiency was lower, because thecoil was not simply taken out of the iron core. Furthermore, the statorhaving the coil impregnated with resin or treated with vanish had theproblem that the coil was degraded in the insulating property orvibration resistance in the AC dynamo for vehicle to be employed in thesevere environments, even though it was easily resolved.

SUMMARY OF THE INVENTION

This invention has been achieved to solve the above-mentioned problems,and it is an object of the invention to provide a stator in which a coilis easily resolved, and a method and device for resolving the stator inwhich the coil can be withdrawn in a short time with a excellent yield.

The present invention provides a stator including a cylindrical ironcore, a slots and a coil disposed in the slots. A portion with a lowerradial crushing strength is provided in at least a part of the iron corein a circumferential direction. The slot is provided around an innercircumferential face of the cylindrical iron core and including anopening portion.

Also, this invention provides a method for resolving a stator includinga step of enlarging the opening portion of the slot, and a step ofextracting the coil from the slot. The stator including a coil disposedin the slots provided around an inner circumferential face of acylindrical iron core and including an opening portion.

Also, this invention provides a method for resolving a stator includinga step of dividing the iron core in a circumferential direction, and astep of extracting the coil from the slot. The stator including a coildisposed in the slots provided around an inner circumferential face of acylindrical iron core and including an opening portion.

Also, this invention provides a device for resolving a stator includingan enlarging section and an extracting section. The enlarging sectionenlarges the opening portion of the slot. An extracting section extractsthe coil from the slot. The stator including a coil disposed in theslots provided around an inner circumferential face of a cylindricaliron core and including an opening portion.

Also, this invention provides a device for resolving a stator includinga dividing section and an extracting section. The dividing sectiondivides the iron core in a circumferential direction. The extractingsection extracts the coil from the slot. The stator including a coildisposed in the slots provided around an inner circumferential face of acylindrical iron core and including an opening portion.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of this invention will becomemore fully apparent from the following detailed description taken withthe accompanying drawings in which:

FIGS. 1A to 1C are explanatory views for explaining a step of enlargingan opening portion of slot and enlarging section according to anembodiment 1 of this invention;

FIG. 2 is an explanatory view for explaining a step of extracting thecoil from the slot and extracting section according to the embodiment 1of this invention;

FIG. 3 is a perspective view of a stator in an AC dynamo for vehicle;

FIG. 4 is a perspective view of an iron core for the stator in the ACdynamo for vehicle;

FIGS. 5A and 5B are explanatory views for explaining a step of enlargingan opening portion of slot and extracting the coil from the slot andmeans according to an embodiment 2 of this invention;

FIGS. 6A and 6B are explanatory views for explaining a step of dividingan iron core in a circumferential direction and extracting the coil fromthe slot and means according to an embodiment 3 of this invention;

FIG. 7 is a perspective view of a stator in an AC dynamo for vehicleaccording to an embodiment 4 of this invention;

FIG. 8 is a perspective view of a strip iron core in the statoraccording to the embodiment 4 of this invention;

FIG. 9 is a front view of an iron core in the shape of annulus ringformed from the strip iron core according to the embodiment 4 of thisinvention;

FIG. 10 is a partial cross-sectional view of a cylindrical statoraccording to the embodiment 4 of this invention;

FIG. 11 is an explanatory view for explaining a step of dividing theiron core in the circumferential direction and dividing sectionaccording to the embodiment 4 of this invention;

FIG. 12 is an explanatory view for explaining a step of enlarging anopening portion of slot and enlarging section according to theembodiment 4 of this invention;

FIG. 13 is an explanatory view for explaining a stator formed like planeover the entire face according to the embodiment 4 of this invention;

FIG. 14 is a partial cross-sectional view showing a part of the statorformed like plane according to the embodiment 4 of this invention;

FIG. 15 is a perspective view of an iron core according to an embodiment5 of this invention;

FIG. 16 is a perspective view of the iron core according to theembodiment 5 of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiment 1

Referring to FIGS. 1A to 4, an embodiment 1 of this invention will bedescribed below. The same or like parts are designated by the samenumerals throughout the figures. FIG. 3 is a perspective view of astator in an AC dynamo for vehicle, and FIG. 4 is a perspective view ofan iron core. FIGS. 3 and 4 are the same views as FIGS. 6A and 8disclosed in JP-A-9-103052. In FIGS. 3 and 4, a stator 1 has the ironcore 2 and a coil 3, the iron core 2 being formed cylindrically byhelically winding a band plate cut out from a strip steel plate. Theiron core 2 has a plurality of slots 4 and teeth 5 around its innercircumferential face, each slot 4 having an opening portion 4 a. A coreback 6 of the iron core 2 has the concave portions 7 corresponding tothe number and size of slots. The coil 3 of copper wire windings isinserted into the slots 4 of the iron core 2 through the openingportions 4 a, and treated with vanish, whereby the stator 1 is builtinto the AC dynamo for vehicle.

FIG. 1A to 1C are explanatory views for explaining a step of enlargingthe opening portion of slot and enlarging section. When the coil 3 ofthe stator 1 is resolved to recycle the copper wire, the stator 1 ispressed via the plate 8 by a press, as shown in FIG. 1A, whereby a partof the outer circumferential face 2 a of the iron core 2 is formed likeplane, as shown in FIG. 1B. FIG. 2 is an explanatory view for explaininga step of extracting the coil from the slot and extracting section. Thepart of the coil 3 for which the outer circumferential face 2 a of theiron core 2 is formed like plane in FIG. 1B is pressed to the innercircumference from both axial end faces of the iron core 2 at the sametime, employing a coil extracting jig 9. Moreover, there is a step ofrotating the stator 1 relative to the pressing direction as shown inFIGS. 1B and 1C, with rotator consisting of a motor. The other part ofthe coil 3 where the outer circumferential face 2 a of the iron core 2is not formed like plane in FIG. 1B has the outer circumferential face 2a formed like plane in the same manner as in FIG. 1B by rotating thestator 1 and pressing the plate 8 by press, as shown in FIG. 1C, andpressed again by the press, employing the coil extracting jig 9.

Since the outer circumferential face 2 a of the cylindrical iron core 2is formed like plane as above described, the opening portion 4 a of theslot 4 is easily enlarged, so that the coil 3 is likely to be extractedwithout interference. Also, since the coil 3 on both end faces of theiron core 2 is pressed at the same time, the coil 3 is surely extractedin a short time. Furthermore, since a step of rotating the stator 1 isprovided, the coil 3 is likely to be extracted as a whole, resulting inan excellent yield. In this manner, since a step of enlarging theopening portion 4 a of the slot 4 and a step of extracting the coil 3are provided, the opening portion 4 a is enlarged even when it isnarrow, whereby the coil 3 is extracted easily and surely in a shorttime. When the vanish treatment is made, there is especially the greateffect, whereby the iron core 2 and the coil 3 are unfixed and the coil3 is more likely to be extracted.

Also, since there are provided enlarging section for enlarging theopening portion 4 a of the slot 4 by pressing the outer circumferentialface 2 a of the iron core 2 by the press and extracting section forextracting the coil 3 from the slot 4 employing the coil extracting jig9, the opening portion 4 a is easily enlarged, and the coil 3 is easilyextracted through the enlarged opening portion 4 a, whereby theresolving device is simple and reduced in size. Also, since there isprovided rotator for rotating the position of the stator 1 relatively,the stator 1 is rotated to enlarge the opening portion 4 a, and extractthe coil 3, whereby the coil 2 is likely to be extracted as a whole,resulting in the resolving device of small size and with excellentyield.

Embodiment 2

Referring to FIGS. 5A and 5B, an embodiment 2 of this invention will bedescribed below. FIGS. 5A and 5B are explanatory views for explaining astep of enlarging the opening portion of slot and extracting the coilfrom the slot and means thereof. FIG. 5A is a front view, and FIG. 5B isa cross-sectional view taken along the line A-A in FIG. 5A. In FIGS. 5Aand 5B, there are provided a pressing jig 10 for pressing the outercircumferential face 2 a of the stator 1 toward the inner circumference,and a coil extracting jig 11 employed with the pressing jig 10 andcapable of pressing separately from the pressing jig 10. Also, rotatorfor rotating the position of the stator 1 such as a motor is provided,whereby the stator 1 is rotated relative to the pressing jig 10 and thecoil extracting jig 11, so that the coil is pressed multiple times. Thecoil extracting jig 11 has a shape of pressing the coil 3 on both endfaces of the iron core 2 at the same time, whereby the coil 3 is pressedby the coil extracting jig 11 while the outer circumferential face 2 aof the iron core 2 is pressed by the pressing jig 10. Also, the stator 1is preheated by heater such as a heating furnace.

As constituted above, in addition to the effects of the embodiment 1,the embodiment 2 has the effect that because the pressing jig 10 and thecoil pressing jig 11 are used in combination, enlargement of the openingportion 4 a and extraction of the coil 3 are made at the almost sametime, resulting in the enhanced resolving efficiency. Also, by combiningenlargement of the opening portion 4 a and extraction of the coil 3 androtation of the position of the stator 1, the coil 3 is likely to beextracted as a whole, resulting in the excellent yield and enhancedresolving efficiency. Also, the small resolving device with excellentresolving efficiency and yield is obtained. Moreover, the coil 3 ispressed multiple times, whereby the coil 3 is likely to be extracted,with small load, and the resolving device is reduced in size.

Since the stator 1 is preheated, the coating or vanish of the coil 3 issoftened or burnt, so that the coil 3 is extracted easily and surely.Also, since heater such as a heating furnace is provided, the coil 3 islikely to be extracted, and the pressing load is decreased, whereby theresolving device is reduced in size, and constituted in line with theheating furnace, with the enhanced resolving efficiency. Moreover, theouter circumferential face 2 a of the iron core 2 is pressed by thepressing jig 10 while the coil is pressed by the coil extracting jig 11,whereby the coil 3 is extracted by a required minimum pressure, so thatthe resolving device is reduced in size.

Embodiment 3

Referring to FIGS. 6A and 6B, an embodiment 3 of this invention will bedescribed below. FIGS. 6A and 6B are explanatory view for explaining astep of dividing the iron core in a circumferential direction andextracting the coil from the slot and means. FIG. 6A is an explanatoryview showing the stator 1 divided along the line B-B, and FIG. 6B is anexplanatory view for explaining how to extract the coil 3 from thedivided stator 1. As shown in FIG. 6A, the stator 1 is divided into twopieces along the line B-B, employing dividing section such as a cutter.Moreover, the divided stator 1 is placed, and the coil 3 is pressed by acoil extracting jig 12 as extracting section for extracting the coil 3and then extracted from the stator 1, as shown in FIG. 6B.

As above constituted, the rigidity of the stator 1 is decreased, becausethe stator 1 is divided, whereby the coil 3 is extracted under a smallerpressure. Also, since the stator 1 is divided, the coil 1 is cut andmore likely to be extracted. Accordingly, the resolving device withsimple constitution and of small size is obtained. Heater such as aheating furnace may be provided, whereby the divided stator 1 is heatedby the heater and then pressed by the coil extracting jig 12 to extractthe coil 3 more easily, with smaller pressing load, whereby theresolving device is reduced in size. Moreover, the divided stator 1 asshown in FIG. 6B may be pressed by the press to take the shape of plane,and then the coil 3 may be extracted, whereby the coil 3 is extractedeasily and the resolving device is constituted simply.

Embodiment 4

Referring to FIGS. 7 to 14, an embodiment 4 will be described below.FIG. 7 is a perspective view of the stator in an AC dynamo for vehicle,FIG. 8 is a perspective view of a strip iron core, and FIG. 9 is a frontview of the iron core in the shape of annulus ring formed from the stripiron core. In FIG. 8, the strip iron core 13 is constituted by forming aband plate having a plurality of slots 14 and teeth 15 from a stripsteel plate using the press and laminating a plurality of band plates.The slot 14 of the iron core 13 have the opening portion 14 a, and hasan abutting surface 16 on both end faces of the strip iron core 13. Acylindrical stator 18 is constituted by disposing a coil 17 in the slots14 of the strip iron core 13, forming the iron core 13 in the shape ofannulus ring, partially welding the abutting surfaces 16, and making thevanish treatment, as shown in FIG. 7.

In FIG. 9, the welding of the abutting surfaces will be described below.The abutting surfaces 16 are abutted with half teeth 15 a and 15 b, andwelded axially at C point on the outer circumferential face 13 a of theiron core 13. Therefore, the abutting surfaces 16 have a lower radialcrushing strength than the other portions. In FIG. 9, the coil 17 isomitted for simplification. FIG. 10 is a partial cross-sectional view ofthe cylindrical stator. The stator 18 has the coil 17 disposed in theslots 14 as shown in FIG. 10, and impregnated with vanish. The openingsize t1 of the opening portion 14 a of the slot 14 is smaller than thewidth W of the coil 17.

FIG. 11 is an explanatory view for explaining a step of dividing theiron core in the circumferential direction and dividing section. In FIG.11, the abutting surfaces 16 of the stator 18 are pressed in an Xdirection, in the Y1 or Y2 direction, or in the X direction and the Y1and Y2 directions to constitute the dividing section. FIG. 12 is anexplanatory view for explaining a step of enlarging the opening portionof slot and enlarging section. In FIG. 12, the rollers 19 as enlargingsection are inserted into the divided stator 18, and moved underpressure, thereby forming at least a part of the outer circumferentialface 13 a of the iron core 13 like plane. Thereafter, the coil 17 ispressed and extracted, employing a jig like the coil extracting jig 9 ofFIG. 2.

FIG. 13 is an explanatory view for explaining a stator formed like planeover the entire face. The stator 13 of FIG. 12 is further formed likeplane over the entire face by the press, and then the coil 17 isextracted by a coil extracting jig, not shown. FIG. 14 is a partialcross-sectional view showing a part of the stator formed like plane. Bymaking the outer circumferential face 13 a of the iron core 13 planar,the opening portion 14 a of the slot 14 is enlarged (t2>t1). Also, evenwhen the coil 17 is impregnated with vanish, the coil 17 is exfoliatedfrom the iron core 13 along with the enlargement of the opening portion14 a.

As above constituted, the stator 18 in which the strip iron core 13 isdisposed in the coil 17 and formed in the shape of annulus ring iseasily divided along the abutting surfaces 16 under the pressure,because a portion with lower radial crushing strength is provided in asection of the iron core 13 in the circumferential direction bypartially welding the abutting surfaces 16 of the iron core 13, wherebyit is possible to produce the stator 18 for the coil 17 is easilyresolved. Though the abutting surfaces 16 on the side of the outercircumferential face 13 a of the iron core 13 are welded, the surfaceportion on the side of the inner circumferential face may be weldedthough it is degraded in the radial crushing strength as compared withthe other portion. Because of this portion having lower radial crushingstrength, the coil is likely to be resolved even after the vanishtreatment, whereby the stator 18 having excellent heat resistance andvibration resistance is produced.

Since the stator 18 is divided, the stator 18 has a lower rigidity,whereby the coil 17 is easily extracted. Also, the coil 17 is cut, andis likely to be extracted. Since the iron core 13 is divided at oneposition in the circumferential direction, the coil 17 is easilydivided, whereby there is an insignificant loss in the yield.Accordingly, the resolving device has a simple constitution, and isreduced in size. The stator may be divided at one position using cuttingsection such as a cutter. By making the outer circumferential face 13 aof the iron core 13 planar, the opening portion 14 a of the slot 14 isenlarged to allow the coil 17 to be easily extracted. Due to dividing,the opening portion 14 a is easily enlarged. In the case where thestator 18 has a smaller size of the opening portion 14 a or a largeamount of vanish impregnation, the opening portion 14 a maybe enlargedin the direction of further enlarging the opening portion 14 a. Becausethe enlarging section for enlarging the opening portion 14 a isprovided, the coil 17 is likely to be extracted, whereby the resolvingdevice is reduced in size.

Embodiment 5

Referring to FIGS. 15 and 16, an embodiment 5 of this invention will bedescribed below. FIGS. 15 and 16 are the perspective views of the ironcore. FIG. 15 is different from FIG. 16 in that the iron core 2 has anotch portion 20. The notch portion 20 is provided as a linear slit whena band plate is cut out from the strip steel plate, and the band plateis wound helically and formed cylindrically, so that the slits areabutted as shown in FIG. 15, whereby the notch portion 20 without gap ismade at four positions at an interval of 90 degrees. In FIG. 16, theconcave portion 7 of the iron core 2 is made larger at four positions atan interval of 90 degrees than the iron core 2 of FIG. 4. The largerconcave portion 21 is provided than other portion when a band plate iscut out from the strip steel plate, and the band plate is woundhelically and formed cylindrically, whereby the larger concave portion21 is provided at four positions at an interval of 90 degrees, as shownin FIG. 16.

As above constituted, each of the notch portion 20 and the concaveportion 21 has a portion of the iron core 2 with lower radial crushingstrength in the circumferential direction than other portion, and thisportion is easily deformed by pressing the outer circumferential face 2a of the stator 1 using this iron core 2 as shown in FIG. 3, so that theopening portion 4 a of the slot 4 is enlarged due to a smaller pressure,whereby the stator 1 for which the coil 3 is easily resolved isproduced. Because of the portion with lower radial crushing strength,the coil is likely to be resolved against the vanish treatment, wherebythe stator 18 having excellent heat resistance and vibration resistanceis obtained. A front bracket and a rear bracket, not shown, are fittedwith both axial faces of the iron core 2 and secured through fourthrough bolts (not shown). If the through bolt and the notch portion 20or concave portion 21 are aligned, there is no practical problem in thedecrease of radial crushing strength, and especially because the concaveportion 21 is increased in size, the through bolt is placed inwarddiametrically, whereby the stator 1 is fixed more securely, and thedevice is reduced in size.

Though the AC dynamo for vehicle has been described by way of example,this invention is widely applicable to the stator for the driving motorfor vehicle or the stator for the motor generator.

As above described, the present invention provides a stator having acoil disposed in the slots provided around an inner circumferential faceof a cylindrical iron core and having an opening portion, characterizedin that a portion with a lower radial crushing strength is provided inat least a part of the iron core in a circumferential direction.Therefore, it is possible to produce the stator in which the coil iseasily resolved, because the iron core is easily deformed in the portionwith lower radial crushing strength. Also, it is possible to produce thestator treated with vanish that is excellent in the heat resistance orvibration resistance, in which the coil is easily resolved.

Also, this invention provides a method for resolving a stator having acoil disposed in the slots provided around an inner circumferential faceof a cylindrical iron core and having an opening portion, characterizedby including a step of enlarging the opening portion of the slot, and astep of extracting the coil from the slot. Therefore, the openingportion of slot is enlarged so that the coil is easily extracted. In thestator treated with vanish, the coil is easily extracted.

Also, this invention provides a method for resolving a stator having acoil disposed in the slots provided around an inner circumferential faceof a cylindrical iron core and having an opening portion, characterizedby including a step of dividing the iron core in a circumferentialdirection, and a step of extracting the coil from the slot. Therefore,the stator has a lower rigidity due to dividing, so that the coil iseasily extracted. Also, since the coil is cut out, the coil is easilyextracted.

Also, this invention provides a device for resolving a stator having acoil disposed in the slots provided around an inner circumferential faceof a cylindrical iron core and having an opening portion, characterizedby comprising enlarging section for enlarging the opening portion of theslot, and extracting section for extracting the coil from the slot.Therefore, the opening portion of slot is enlarged, so that the coil iseasily extracted, whereby the small-sized resolving device can beproduced with excellent resolving efficiency and yield. In the statortreated with vanish, the coil is easily extracted.

Also, this invention provides a device for resolving a stator having acoil disposed in the slots provided around an inner circumferential faceof a cylindrical iron core and having an opening portion, characterizedby comprising dividing section for dividing the iron core in acircumferential direction, and extracting section for extracting thecoil from the slot. Therefore, the stator has a lower rigidity due todividing. Further, since the coil is cutout, the coil is easilyextracted. Consequently, the small-sized resolving device can beproduced with excellent resolving efficiency and yield.

1. A stator comprising: a cylindrical iron core including a plurality ofslots provided around an inner circumferential face of the cylindricaliron core, and a plurality of first concave portions and a secondconcave portion provided in an outer circumferential face of thecylindrical iron core; and a coil disposed in the slots, wherein a depthof the second concave portion is larger than a depth of said firstconcave portions so that the cylindrical iron core has a lower radialcrushing strength at the second concave portion than at other portionsof the cylindrical iron core.
 2. The stator according to claim 1,wherein the cylindrical iron core includes four second concave portionsprovided at intervals of 90 degrees around the outer circumferentialface of the cylindrical iron core.
 3. The stator according to claim 1,wherein the iron core includes a welded portion in which abuttingsurfaces of the iron core are partially welded together.